[%c_effect f5;square;f5;type;Mistake;persistent;true] A serious inaccuracy, after which Black's position becomes surprisingly difficult.
37. g4f5  37... e6f5 It's surprising to me to see Giri lose an endgame like this, but strange things happen in rapid games. 38. h4f2  38... f5e6  39. f2g3 [%c_effect g3;square;g3;type;GreatFind;persistent;true]